pretty cool,
When I am on the road my high end system is my EPC with music encoded in flak into a AMB Y1 DAC, into a AMD Mini3, and my AKG K701. I like this project as it will not require a PC to boot up, a shame you can't offer 2 versions on with just I2S out that would fit in a smaller case (ideal would be the same case used by the AMB). I still may buy one (if they become available) to add to my many small boxes that drive the TSA people nuts at the airports.

Fragmented files are mainly a problem with a HDD where you have different seek times depending on the physical location of sectors on the disk. Continuous reads (non-fragmented) mainly have track to track delays that are smaller compared to random read delays (fragmented files).

With the SD-card these delays are different and mainly depend on SD-card on-chip controller properties.

We tried to maximize margin for errors by using fastest possible data transfers between SD-card and DCI module:

- We use double SPI clock speed compared to Koons project.
- The SD-card data is directly loaded into the DCI module without byte swapping or stuffing bytes with the value 0 (required for 64 bits / frame). This is possible by using 32 bits / frame.
- Microchip FAT16/32 libraries are used.

Main objective was designing a digital audio source that eliminates major drawbacks of conventional digital audio sources, thus providing much better digital audio playback quality. Other advantage is the possible construction of small portable audiophile players, running on batteries.

Both front panel PCB and SD-card PCB design have been completed. I attached a screen shot of the design.

The front panel PCB is tailor-made to the standard aluminum housing. It contains 2 blue LED displays (SMD), one orange LED for play / pause indication, segment / digit buffers, and keys.

In the center there is a slot for the replaceable SD-card holder module (lower PCB). The front panel PCB is directly soldered to the main PCB under a 90 degree angle, using double-row pin headers. The SD-card holder module is mounted to the main board using brass hexagonal spacers.

Main board schematics are almost completed.

We also performed some more comparisons with conventional digital audio sources. These appear to be unable to achieve SD-player performance, regardless of DAC chip, reclocker, analogue stages, digital audio interface or power supply.

Note that the SD-card prototype runs on a cheap mains adapter only, power consumption while playing is around 3.5 watts. Required minimum input voltage equals approx. 7 ... 8 volts. All circuits (including the 3-crystal super clock) run on either 3.3 or 5V.

We also fixed two minor software bugs that were discovered during extensive testing. Player now appears to perform rock-solid, card type or brand are not critical, as long as the SD-cards aren't exceptionally slow like some of the first 128 or 256Mb cards. In general SD-card speed rating of 2 or higher works excellent.

There is no jitter free source material (master clock jitter during A/D conversion).

For ease of mind you could use EAC or CD paranoia, I currently use use Grip under Ubuntu / Linux, this application uses CD paranoia.

After ripping, the WAV files can be written to the SD card as follows:

1) First make sure the SD-card is formatted correctly, use FAT32 and include boot sector.

2) Place each CD in a separate directory. All these directories must be placed in the root directory. The directory name must start with a two-digit number, example: 01 - Audiophile Voices Volume I - Various Artists.

3) Copy all WAV files (tracks) of a CD to the corresponding directory. The track names must also start with a two-digit number, example 01 - Over The Rainbow - Jane Monheit.

So it's basically using correct numbering of both directories and tracks, and copy the WAV files to the SD-card.

Suitable SD-card readers are quite cheap (around $5), I use a Transcend SD-card reader. These readers are plugged into a USB socket, SD-card is inserted, and appears as a drive on the desktop.

It's also possible to use micro-SD cards with an adapter.

The player currently supports SD/SDHC cards with a capacity up to 32Gb. This provides room for approx. 50 CDs / card. When the 64Gb cards are available, this is increased to approx. 100 CDs / card.